Today, printing systems are utilized in which host equipment (a client device) such as a host computer and printing devices such as single-function printing devices and so-called all-in-one printing devices are connected via a network. In such a system, there is a high probability that while a print job requested from host equipment with a printing device is being processed, the next print job from different host equipment will be supplied to this printing device.
When print jobs compete, control is possible that does not accept processing of other print jobs until print processing of the first-arrived print job is concluded. However, in this case when the print system is viewed as a whole, efficiency declines and the system has poor user-friendliness. That is to say, while a print job requiring time until printing is completed is being processed first, print processing must wait even for small-volume print jobs needing short printing times. Consequently, when the printing system is considered as a whole, this is a system with poor efficiency as the number of print jobs in a waiting-to-print status increases.
In addition, users must wait a long time until print processing is completed when a print job requiring considerable time until the end of printing is processed first even when the desire is to urgently accomplish printing.
In consideration of the above problem, Unexamined Japanese Patent Application KOKAI Publication No. H10-177464 (hereafter referred to as “Patent Literature 1”) and Unexamined Japanese Patent Application KOKAI Publication No. H11-312062 (hereafter referred to as “Patent Literature 2”) have been disclosed. Even these Patent Literatures are inventions of printing devices having interruption processing for jobs during print processes, interruption printing of urgent print jobs, a reinstatement function for interrupted print jobs and an interruption printing function for executing restarted print processes for interrupted print jobs.
First, Patent Literature 1 discloses a printing control device having two operation modes, namely normal mode and non-printing mode, and operates in non-printing mode until the printing restart page is reached and operates in normal mode from the printing restart page on. The normal mode is an operating mode in which print jobs described in non-page-independent Page Description Language (hereafter called “PDL”) received from a client device are stored in memory, each page of images is created in succession, and the created images are supplied to the printing device and printed. The non-printing mode is an operating mode in which images are not supplied to the printing device. The print control device disclosed in Patent Literature 1 is such that when printing is suspended, a printing restart page is calculated, and when a printing restart signal is received at the time of restarting printing, the suspended print job is processed from the beginning with reference to the job memory unit.
In addition, Patent Literature 2 discloses a printing device wherein the method of restarting a print job suspended by interruption printing is to interpret from the start the suspended print job data when restarting, and to execute print requests for each page. Here, with the printing device disclosed in Patent Literature 2, redundant printing is prevented by adopting a method in which print requests relating to pages already printed are invalid and only print requests for unprinted pages are valid.
However, with both devices, input print jobs are stored and when an interruption request is generated, the job currently being printed is interrupted at the end of a page, and the number of pages already printed or the number of the page to be restarted are stored, and after the interruption process of the print job is accomplished, interruption printing is executed. Moreover, with both devices, when interruption printing ends, command interpretation from the head of the interrupted print job is executed, and a reinstatement/restart process is executed that restarts the print process from the unprinted pages without executing printing of pages already printed. In this print job reinstatement/restart process, because command interpretation is executed from the head of the interrupted print job and a print image is created, the interpretation execution and print image creation are accomplished even for pages that have already been printed and output, requiring a long time until resumption of the print process.
Consequently, when the interruption printing function is used, time is needed to reinstate the interrupted print job (the preceding print job), and as a result this becomes an impediment when using the interruption print function. Accordingly, a printing device is desired that is capable of accomplishing in a short time a reinstatement/restart process from when execution of the interruption printing process ends until printing of the interrupted print job is restarted.
Furthermore, with the invention disclosed in Patent Literature 1, a method is disclosed in which a PDL command creating an image hard-wise is not executed to shorten job reinstatement time, but in this case, circuit size becomes large and in addition logic composition becomes complex, causing costs to rise. Consequently, a printing device is desired that has a relatively simple structure yet is capable of improving performance during interruption reinstatement.
In consideration of the foregoing problems, it is an object of the present invention to provide a printing device with a relatively simple structure and capable of improving performance during interruption reinstatement, a printing system, a print control method and a computer-readable recording medium that is not temporary and tangibly stores a program for realizing this.